Design strategy for blends of biodegradable polyester and thermoplastic starch based on a molecular dynamics study of the phase-separated interface.

Molecular insight into the phase-separated interface formed when biodegradable polyesters and thermoplastic starch (TPS) are melt-blended is valuable for the design of composites. In this study, eight different interfaces combining four major biodegradable polyesters (PLA, PBS, PHB and PBAT) and two TPSs [unmodified TPS (nTPS) and citrate-modified TPS (cTPS)] were investigated by using molecular dynamics (MD) simulations. According to the MD simulation results, PBS, PHB and PBAT diffuse readily into the TPS and form compatible interfaces, whereas PLA is less compatible with the TPS. The results of tensile simulations show that PBS and PBAT adhere well to TPS; in particular, PBS/cTPS and PBAT/cTPS exhibit high interfacial-fracture energy (G). Both PLA and PHB blended with TPS exhibit low G because PLA is less compatible with TPS and PHB and TPS have low electrostatic interaction. The reason for the high G of PBS/cTPS and PBAT/cTPS is thought to be a combination of three factors: (i) formation of a deep compatible interface, (ii) suppression of void growth by electrostatic interactions and (iii) absorption of strain energy by a change in the conformation of the molecular chains. These three interfacial adhesion mechanisms should be considered when designing biodegradable polyester/TPS blends with good mechanical properties.

Effects of Bifidobacterium longum BB536 and Bifidobacterium breve MCC1274 on Body Composition in Normal and Overweight Adults in Randomized Placebo-Controlled Study.

Visceral fat accumulation is considered to be associated with a higher risk of chronic diseases. We investigated the effects of Bifidobacterium longum subsp. longum (B. longum) BB536 and Bifidobacterium breve (B. breve) MCC1274 on body composition, including visceral fat, in a randomized, parallel-group, placebo-controlled study. Participants were between 29 and 64 years of age and had a body mass index (BMI) of greater than 23 and less than 30. One hundred participants were randomly assigned to the probiotics group or placebo group. Participants were administered probiotic capsules containing 1 × 1010 colony-forming units (CFUs) of B. longum BB536 and 5 × 109 CFU of B. breve MCC1274 or placebo capsules without bifidobacteria for 16 weeks. In the probiotics group, abdominal visceral fat area, total abdominal fat area, and serum triglyceride levels were significantly decreased compared to those in the placebo group. Additionally, the increase in BMI observed in the placebo group was significantly suppressed in the probiotics group. This study showed that B. longum BB536 and B. breve MCC1274 reduced abdominal visceral fat and total fat levels in healthy normal and overweight adults, suggesting their beneficial effects on body composition.

Effects of Heat-Killed Lacticaseibacillus paracasei MCC1849 on Immune Parameters in Healthy Adults-A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study.

Previous clinical studies have shown that heat-killed Lacticaseibacillus paracasei MCC1849 suppresses subjective symptoms among healthy adults. However, the mechanism underlying this beneficial effect remains unclear. This clinical study aimed to investigate the effects of MCC1849 on immune functions in humans. In this randomized, double-blind, placebo-controlled, parallel-group study, 100 healthy adults were randomly divided into MCC1849 or placebo groups. Participants ingested test powder with 5 × 1010 MCC1849 cells or placebo powder for 4 weeks. Immune functions were evaluated using expression levels of CD86 and HLA-DR on dendritic cells (DCs), neutrophils, and natural killer cells. The expression levels of interferon (IFN)-α, -ß, and -γ in peripheral blood mononuclear cells incubated with Cpg2216 in vitro were quantified. Efficacy analysis was performed on participants in the per-protocol set (placebo group; n = 47, MCC1849 group; n = 49). The expression level of CD86 on pDCs and the gene expression levels of IFN-α, -ß, and -γ upon TLR9 agonist stimulation were significantly higher in the MCC1849 group at 4 weeks. No side effects were observed. This is the first report to show the positive effects of MCC1849 on human immune cells. These findings reveal one possible mechanism of how MCC1849 suppresses subjective symptoms.

Bifidobacterium breve M-16V regulates the autonomic nervous system via the intestinal environment: A double-blind, placebo-controlled study.

We conducted a randomized controlled trial to investigate the potential of Bifidobacterium breve M-16 V to improve mood in humans. In this evaluation, we incorporated the use of near-infrared spectroscopy (NIRS), which has been used to evaluate mood states in studies with small sample sizes. Participants were given B. breve M-16 V (20 billion cells/day) for 6 weeks, and their mood state was assessed before and after ingestion. NIRS data were collected at rest and during a mental arithmetic task (under stress). Intake of B. breve M-16 V decreased the heart rate under stress and increased levels of the GABA-like substance pipecolic acid in stool samples. In addition, B. breve M-16 V improved mood and sleep scores in participants with high anxiety levels. These results suggest that B. breve M-16 V affects the metabolites of the gut microbiota and has the potential to modulate the autonomic nervous system and to improve mood and sleep.

Quantitative Imaging of Genetically Encoded Fluorescence Lifetime Biosensors.

Genetically encoded fluorescence lifetime biosensors have emerged as powerful tools for quantitative imaging, enabling precise measurement of cellular metabolites, molecular interactions, and dynamic cellular processes. This review provides an overview of the principles, applications, and advancements in quantitative imaging with genetically encoded fluorescence lifetime biosensors using fluorescence lifetime imaging microscopy (go-FLIM). We highlighted the distinct advantages of fluorescence lifetime-based measurements, including independence from expression levels, excitation power, and focus drift, resulting in robust and reliable measurements compared to intensity-based approaches. Specifically, we focus on two types of go-FLIM, namely Förster resonance energy transfer (FRET)-FLIM and single-fluorescent protein (FP)-based FLIM biosensors, and discuss their unique characteristics and benefits. This review serves as a valuable resource for researchers interested in leveraging fluorescence lifetime imaging to study molecular interactions and cellular metabolism with high precision and accuracy.

Effects of Heat-Killed Lacticaseibacillus paracasei MCC1849 on the Maintenance of Physical Condition in Healthy Adults: A Randomized, Double-Blind, Placebo-Controlled, Parallel-Group Study.

We previously reported that the intake of heat-killed Lacticaseibacillus paracasei MCC1849 suppressed the onset of cold-like symptoms in healthy young women who were susceptible to colds. This study aimed to investigate the effects of MCC1849 on subjective symptoms of physical condition in healthy adults of a wide age range. In this randomized, double-blind, placebo-controlled, parallel-group study, 200 healthy adults were randomly divided into the MCC1849 group or placebo group. The participants received test powder with 50 billion MCC1849 cells or placebo powder without MCC1849 for 24 weeks. Subjective symptoms were assessed by diary scores. Analysis was performed on 183 participants (MCC1849 group; n = 91, placebo group; n = 92) in the per-protocol set. The number of days of stuffy nose and cold-like symptoms was significantly reduced in the MCC1849 group compared with the placebo group. In addition, the duration of stuffy nose, sore throat and cold-like symptoms was significantly lower in the MCC1849 group. No side effects were observed. Therefore, oral intake of MCC1849 suppressed subjective symptoms in healthy adults of a wide age range. These data suggest that MCC1849 may help maintain physical condition.

Radical Caging Strategy for Cholinergic Optopharmacology.

Photo-caged methodologies have been indispensable for elucidating the functional mechanisms of pharmacologically active molecules at the cellular level. A photo-triggered removable unit enables control of the photo-induced expression of pharmacologically active molecular function, resulting in a rapid increase in the concentration of the bioactive compound near the target cell. However, caging the target bioactive compound generally requires specific heteroatom-based functional groups, limiting the types of molecular structures that can be caged. We have developed an unprecedented methodology for caging/uncaging on carbon atoms using a unit with a photo-cleavable carbon-boron bond. The caging/uncaging process requires installation of the CH2-B group on the nitrogen atom that formally assembles an N-methyl group protected with a photoremovable unit. N-Methylation proceeds by photoirradiation via carbon-centered radical generation. Using this radical caging strategy to cage previously uncageable bioactive molecules, we have photocaged molecules with no general labeling sites, including acetylcholine, an endogenous neurotransmitter. Caged acetylcholine provides an unconventional tool for optopharmacology to clarify neuronal mechanisms on the basis of photo-regulating acetylcholine localization. We demonstrated the utility of this probe by monitoring uncaging in HEK cells expressing a biosensor to detect ACh on the cell surface, as well as Ca2+ imaging in Drosophila brain cells (ex vivo).

An EBSD camera as a tool to characterise in-plane magnetisation vectors on Fe-Si (001) surface.

Previous studies have shown that type-II magnetic-domain contrasts are caused by differences in the backscattering yields of magnetic domains of opposite magnetisation. Imaging the magnetic domains when the magnetisation vectors in the opposite-magnetisation domains are perpendicular to the tilt axis of the specimen has been considered difficult, because of the lack of change in the backscattering yields between the domains. An alternative way to obtain the type-II magnetic-domain contrasts is to utilise the difference in the exit angular distribution of the backscattered electrons from different magnetic domains. In this study, it is found that an electron backscatter diffraction (EBSD) camera can be used to obtain the type-II magnetic-domain contrasts caused by the above two mechanisms simultaneously. We verify this by distinguishing all four possible in-plane magnetisation vectors on a Fe-Si (001) surface without a sample rotation, using an EBSD detector as an array of electron detectors. The change in contrast between the magnetic domains, with respect to the location of a virtual electron detector, can provide information on the directions of the magnetisation vectors. A method to suppress the topographic contrast superimposed on the magnetic-domain contrast is also demonstrated.

Molecular insight into toughening induced by core-shell structure formation in starch-blended bioplastic composites.

Binary and ternary blends with poly(lactic acid) (PLA), poly(butylene succinate) (PBS), and thermoplastic starch (TPS) were prepared by a melt process to produce biodegradable biomass plastics with both economical and good mechanical properties. The mechanical and structural properties of each blend were evaluated. Molecular dynamics (MD) simulations were also conducted to examine the mechanisms underlying the mechanical and structural properties. PLA/PBS/TPS blends showed improved mechanical properties compared with PLA/TPS blends. The PLA/PBS/TPS blends with a TPS ratio of 25-40 wt% showed higher impact strength than PLA/PBS blends. Morphology observations showed that in the PLA/PBS/TPS blends, a structure similar to that of core-shell particles with TPS as the embedding phase and PBS as the coating phase was formed, and that the trends in morphology and impact strength changes were consistent. The MD simulations suggested that PBS and TPS tightly adhered to each other in a stable structure at a specific intermolecular distance. From these results, it is clear that PLA/PBS/TPS blends are toughened by the formation of a core-shell structure in which the TPS core and the PBS shell adhered well together and stress concentration and energy absorption occurred in the vicinity of the core-shell structure.

Early Probiotic Supplementation of Healthy Term Infants with Bifidobacterium longum subsp. infantis M-63 Is Safe and Leads to the Development of Bifidobacterium-Predominant Gut Microbiota: A Double-Blind, Placebo-Controlled Trial.

Bifidobacteria are important intestinal bacteria that provide a variety of health benefits in infants. We investigated the efficacy and safety of Bifidobacterium longum subsp. infantis (B. infantis) M-63 in healthy infants in a double-blind, randomized, placebo-controlled trial. Healthy term infants were given B. infantis M-63 (n = 56; 1 × 109 CFU/day) or placebo (n = 54) from postnatal age ≤ 7 days to 3 months. Fecal samples were collected, and fecal microbiota, stool pH, short-chain fatty acids, and immune substances were analyzed. Supplementation with B. infantis M-63 significantly increased the relative abundance of Bifidobacterium compared with the placebo group, with a positive correlation with the frequency of breastfeeding. Supplementation with B. infantis M-63 led to decreased stool pH and increased levels of acetic acid and IgA in the stool at 1 month of age compared with the placebo group. There was a decreased frequency of defecation and watery stools in the probiotic group. No adverse events related to test foods were observed. These results indicate that early supplementation with B. infantis M-63 is well tolerated and contributes to the development of Bifidobacterium-predominant gut microbiota during a critical developmental phase in term infants.

The Potential Immunomodulatory Effect of Bifidobacterium longum subsp. longum BB536 on Healthy Adults through Plasmacytoid Dendritic Cell Activation in the Peripheral Blood.

The interaction between the gut microbiota and the host can influence the host's immune system. Bifidobacterium, a commensal genus of gut bacteria, seems to have positive effects on host health. Our previous clinical research showed that B. longum subsp. longum BB536 enhanced innate and adaptive immune responses in elderly individuals with a lower grade of immunity, but the immunomodulatory mechanism is still unclear. In this study, dendritic cell (DC) surface markers in peripheral blood mononuclear cells isolated from healthy individuals were evaluated through coculture with heat-killed BB536. DC markers, innate immune activity and cytokine levels in plasma were also evaluated by a randomized, double-blind, placebo-controlled, parallel-group study (UMIN000045564) with 4 weeks of continuous live BB536 intake. BB536 significantly increased the expression of CD86 and HLA-DR on plasmacytoid DCs (pDCs) in vitro. Compared to placebo (n = 48), a significant increase in the expression of CD86 on peripheral pDCs was detected at week 4 of live BB536 intake (n = 49; 1 × 1010 CFU/day). Furthermore, coculture with hk-BB536 significantly increased the IFNγ expression level and demonstrated trends of increased IFNα1 and IFNß expression. These findings suggest that consumption of BB536 has potential immunomodulatory effects on healthy individuals through the activation of peripheral pDCs.

A palette of site-specific organelle fluorescent thermometers.

Intracellular micro-temperature is closely related to cellular processes. Such local temperature inside cells can be measured by fluorescent thermometers, which are a series of fluorescent materials that convert the temperature information to detectable fluorescence signals. To investigate the intracellular temperature fluctuation in various organelles, it is essential to develop site-specific organelle thermometers. In this study, we develop a new series of fluorescent thermometers, Thermo Greens (TGs), to visualize the temperature change in almost all typical organelles. Through fluorescence lifetime-based cell imaging, it was proven that TGs allow the organelle-specific monitoring of temperature gradients created by external heating. The fluorescence lifetime-based thermometry shows that each organelle experiences a distinct temperature increment which depends on the distance away from the heat source. TGs are further demonstrated in the quantitative imaging of heat production at different organelles such as mitochondria and endoplasmic reticulum in brown adipocytes. To date, TGs are the first palette batch of small molecular fluorescent thermometers that can cover almost all typical organelles. These findings can inspire the development of new fluorescent thermometers and enhance the understanding of thermal biology in the future.

Squaraine probes for the bimodal staining of lipid droplets and endoplasmic reticulum imaging in live cells.

Lipid droplets (LDs) have emerged as a hot target for cancer therapeutics in recent years owing to findings that have shown them to be key organelles involved in maintaining cellular stability and regulating inter-organelle communication through molecular trafficking. LDs emerge from the endoplasmic reticulum (ER) as a form of cellular homeostasis control. We herein report the study of a library of asymmetric squaraines as superior fluorescence probes to track and image LDs in their native state and environment within cancer cells. The probes are highly selective towards LDs and displayed prominent bright fluorescence with just 1 µM probe concentration. They also possess bimodal LD and ER staining capability via the simple diffusion of small lipophilic molecules. The probes almost instantly stained LDs, while the ER staining rate is dependent on the probe's lipophilicity and the incubation duration. These "on-demand" organelle-selective probes are highly desirable tools for revealing the role of LDs in governing many cellular processes, especially in malignant cells.

Modulation of Local Cellular Activities using a Photothermal Dye-Based Subcellular-Sized Heat Spot.

Thermal engineering at the microscale, such as the regulation and precise evaluation of the temperature within cellular environments, is a major challenge for basic biological research and biomaterials development. We engineered a polymeric nanoparticle having a fluorescent temperature sensory dye and a photothermal dye embedded in the polymer matrix, named nanoheater-thermometer (nanoHT). When nanoHT is illuminated with a near-infrared laser at 808 nm, a subcellular-sized heat spot is generated in a live cell. Fluorescence thermometry allows the temperature increment to be read out concurrently at individual heat spots. Within a few seconds of an increase in temperature by approximately 11.4 °C from the base temperature (37 °C), we observed the death of HeLa cells. The cell death was observed to be triggered from the exact local heat spot at the subcellular level under the fluorescence microscope. Furthermore, we demonstrate the application of nanoHT for the induction of muscle contraction in C2C12 myotubes by heat release. We successfully showed heat-induced contraction to occur in a limited area of a single myotube based on the alteration of protein-protein interactions related to the contraction event. These results demonstrate that even a single heat spot provided by a photothermal material can be extremely effective in altering cellular functions.

Heat-sterilized Bifidobacterium breve prevents depression-like behavior and interleukin-1ß expression in mice exposed to chronic social defeat stress.

Major depressive disorder (MDD) is a common and serious psychiatric disease that involves brain inflammation. Bifidobacterium breve is commonly used as a probiotic and was shown to improve colitis and allergic diseases by suppressing the inflammatory response. Heat-sterilized B. breve has beneficial effects on inflammation. We hypothesize, therefore, that this probiotic might reduce depression symptoms. We tested this is a mouse model of social defeat stress. C57BL/6J mice exposed to chronic social defeat stress (CSDS) for five consecutive days developed a mild depression-like behavior characterized by a social interaction impairment. CSDS also altered the gut microbiota composition, such as increased abundance of Bacilli, Bacteroidia, Mollicutes, and Verrucomicrobiae classes and decreased Erysipelotrichi class. The prophylactic effect of heat-sterilized B. breve as a functional food ingredient was evaluated on the depression-like behavior in mice. The supplementation started two weeks before and lasted two weeks after the last exposure to CSDS. Two weeks after CSDS, the mice showed deficits in social interaction and increased levels of inflammatory cytokines, including interleukin-1ß (IL-1ß) in the prefrontal cortex (PFC) and hippocampus (HIP). Heat-sterilized B. breve supplementation significantly prevented social interaction impairment, suppressed IL-1ß increase in the PFC and HIP, and modulated the alteration of the gut microbiota composition induced by CSDS. These findings suggest that heat-sterilized B. breve prevents depression-like behavior and IL-1ß expression induced by CSDS through modulation of the gut microbiota composition in mice. Therefore, heat-sterilized B. breve used as an ingredient of functional food might prevent MDD.

Epo-C12 inhibits peroxiredoxin 1 peroxidase activity.

Epo-C12 is a synthetic derivative of epolactaene, isolated from Penicillium sp. BM 1689-P. Epo-C12 induces apoptosis in human acute lymphoblastoid leukemia BALL-1 cells. In our previous studies, seven proteins that bind to Epo-C12 were identified by a combination of pull-down experiments using biotinylated Epo-C12 (Bio-Epo-C12) and mass spectrometry. In the present study, the effect of Epo-C12 on peroxiredoxin 1 (Prx 1), one of the proteins that binds to Epo-C12, was investigated. Epo-C12 inhibited Prx 1 peroxidase activity. However, it did not suppress its chaperone activity. Binding experiments between Bio-Epo-C12 and point-mutated Prx 1s suggest that Epo-C12 binds to Cys52 and Cys83 in Prx 1. The present study revealed that Prx 1 is one of the target proteins through which Epo-C12 exerts an apoptotic effect in BALL-1 cells.

Immuno-modulation by heat-killed Lacticaseibacillus paracasei MCC1849 and its application to food products.

Probiotics are microorganisms that confer health benefits to host. Well-known examples include Bifidobacterium and Lactobacillus species. In recent years, interest in promoting our health with probiotics has grown as life expectancy and health awareness has increased. However, some concerns for safety and stability exist for these live organisms. Thus, "postbiotics" and "paraprobiotics," non-viable heat-killed microbial cells or cell fractions that retain health benefits, are increasingly favored. Unfortunately, little information on clinical efficacy and mechanisms of action is available compared with many available probiotics. Lacticaseibacillus (previous name Lactobacillus) paracasei MCC1849 is a commonly used lactic acid bacterial strain in Japan that displays immuno-modulatory effects in humans in non-viable heat-killed form. This review discusses health benefits of heat-killed L. paracasei MCC1849 immune modulation and offers a theoretical basis for its mechanisms of action. We also discuss the feasibility of using heat-killed probiotics for application in food products.

An affinity change model to elucidate the rotation mechanism of V1-ATPase.

V-ATPases are ubiquitous proton-transporting ATPases of eukaryotic and prokaryotic membranes that utilize energy from ATP hydrolysis. The hydrophilic catalytic part called V1-ATPase is composed of a ring-shaped hexametric A3B3 complex and a central DF shaft. We previously proposed a rotation mechanism of the Enterococcus hirae V1-ATPase based on the crystal structures of the V1 and A3B3 complexes. However, the driving force that induces the conformational changes of A3B3 and rotation of the DF shaft remains unclear. In this study, we investigated the binding affinity changes between subunits of V1-ATPase by surface plasmon resonance analysis. The binding of ATP to subunit A was found to considerably increase the affinity between the A and B subunits, and thereby ATP binding contributes to forming the A1B1 tight conformation. Furthermore, the DF shaft bound to the reconstituted A1B1 complex with high affinity, suggesting that the tight A1B1 complex is a major binding unit of the shaft in the A3B3 ring complex. Based on these results, we propose that rotation of the V1-ATPase is driven by affinity changes between each subunit via thermal fluctuations.

Ultra-thin, transparent, porous substrates as 3D culture scaffolds for engineering ASC spheroids for high-magnification imaging.

Three-dimensional (3D) culture is expected to reproduce biological tissues more representatively than monolayer culture, which is important for in vitro research such as drug screening. Recently, various cell culture substrates for spheroid engineering have been developed based on the prevention of cell adhesion. However, despite the expanded usability these substrates provide, they remain limited in terms of optical microscopy imaging of spheroids with high magnification lenses. This is because almost all substrates generated by nanoimprinting hamper the light passing through them owing to their low optical transparency caused by the thickness and surface structure. In this study, we achieved the preparation of spheroids from adipose-tissue derived stem cells (ASCs) on free-standing porous polymeric ultrathin films ("porous nanosheets") consisting of poly(d,l-lactic acid) (PDLLA) with thickness of 120 nm and average pore diameter of 4 µm. ASCs migrated on the porous nanosheet, leading to the spontaneous organization of spheroids anchored via a cell monolayer. The porous nanosheet also provided more than twice the optical transparency in confocal and holographic microscopy observation compared to conventional nanoimprinted substrates for 3D cell culture (NanoCulture Dish). The internal structure of the organized spheroids could be clearly observed with 40× magnification. In addition, the engineered spheroids showed bioactivities indicated by mRNA expression of fibroblast growth factor (FGF-2) and vascular endothelial growth factor (VEGF). Thus, porous nanosheets offer a unique cell culture substrate, not only for engineering 3D cellular organization from stem cells, but also for imaging detailed structure using light microscopy.

Highly cooperative fluorescence switching of self-assembled squaraine dye at tunable threshold temperatures using thermosensitive nanovesicles for optical sensing and imaging.

Thermosensitive fluorescent dyes can convert thermal signals into optical signals as a molecular nanoprobe. These nanoprobes are playing an increasingly important part in optical temperature sensing and imaging at the nano- and microscale. However, the ability of a fluorescent dye itself has sensitivity and accuracy limitations. Here we present a molecular strategy based on self-assembly to overcome such limitations. We found that thermosensitive nanovesicles composed of lipids and a unique fluorescent dye exhibit fluorescence switching characteristics at a threshold temperature. The switch is rapid and reversible and has a high signal to background ratio (>60), and is also highly sensitive to temperature (10-22%/°C) around the threshold value. Furthermore, the threshold temperature at which fluorescence switching is induced, can be tuned according to the phase transition temperature of the lipid bilayer membrane forming the nanovesicles. Spectroscopic analysis indicated that the fluorescence switching is induced by the aggregation-caused quenching and disaggregation-induced emission of the fluorescent dye in a cooperative response to the thermotropic phase transition of the membrane. This mechanism presents a useful approach for chemical and material design to develop fluorescent nanomaterials with superior fluorescence sensitivity to thermal signals for optical temperature sensing and imaging at the nano- and microscales.